Electrolytic production of hypochlorite solutions



H. B. SLATER.

ELECTROLYTIC PRODUCTlON 0F HYPOCHLORITE SOLUTIONS.

APPLICATION FILED Nov1 9. 1920.

L glgo Patented Nov. l5, M9211..

liti

duction HENRY E. SLATER, F RIVIERSXDE, CORMIER;

. nancrnonv'rrc rnonucrrou or rrocnronnrn sorurroivs.

Leonesa,

To all whom t may concern.'

Be it known that l, HENRY B. SLA'rnR, a citizen of the United States of America, residing at Riverside in the county of Riverside and State of California, have invented certain new and useful improvements i` Flectrolytic Production of ll-lypochlorite Solutions, of which the following is a speci-'i cation. f

The present invention relates to the pro-v duction of hypochlorite solutions, particularly the hypochlorites of the alkali metalspi t e pro' of sodium hypochlorite solution, V,

tain the How while maintaining the cell full or approximately full of the electrolyte.

llt will be observed that by this mode ot procedure the sodium is-liberated at the cathode and for the purpose of illustration,

suitable for use as a disinfecting solution, will be particularly described herein.

By the employment of the present invention, the productioncof a hypocllorite solu tion of high concentration of hypochlorite and low concentration of chlorid can be readily effected, and a product vreadily meeting the requirements of the testfor Dakins sodium hypochlorite solution can-readily be secured. f

The accompanying drawings show diagrammatically the preferred construction of an electrolytic cell for employment in accordance with the present invention. .ln said drawings, Figure 1 shows a vertical sectional elevation of the preferred construction of the cell. Fig. 2 shows a plan section, taken approximately Aon. the line 2-2 of Fig. 1 looking downwardly andF ig. 3 is a side view or one of. the electrodes. Fig. 4 is a central vertical section and Fig. 5 a top plan view of modied form ot apparatus for 'carrying out the production ot hypochlorite solution according to the present invention.`

Assuming that sodium chlorid is to be treated,lthis solution entersby the pipe 1,

` and by means of the valve 2 is allowed to how through pipe 3 (the connection between pipe 1 and pipe 4 being closed by said valve 2) the solution -'thereby entering the cell 5 through the pipe 6, which may terminate, as shown, at a point near the het or said cell. ln startin the operation, the air in the cell 5 will rst be expelled to waste through pipe 7, the valve therein being open for` this purpose. 'lheliquor will eventually till the cell 5, whereupon the valve in pipe 3' will be opened and the pole changer 9 will be thrown into the position Specification of Letters Patent.

Application led'lovember 9, 1920. Seriallto. 422,826.

Patented Nov. 15, 1921i.

illustrated, whereby connection is made from the positive terminal to the upper end of the electrode 10 which will thereby become the anode ofthe cell and an electrical connection will be madev from the negative terminal to the upper part of the ellectrode 11, whereby the electrode 1'1 becomes the cathode. 10 and 11 may be made of graphite, if desired. The liquor is allowed to iow continuously through pipe 1, valve 2, pipe 3, inlet 6, through the pertorations 12 in the cathode, through the perforations 13 in the anode and out through pipe 8, the valves 2. and 1t being .suitably adjusted to mainy"111, which-quickly lunites with water to form caustic soda, and this caustic soda Hows toward the right in Fig. 1, into contactwith the anode, whereby an excess of sodium hydroxid solution is 'maintained inv contact with the anode so as to instantaneously absorb the -chlorin liberated at -the anode and the hypochlorite solution then hows ed through pipe 8 without having any substantial portionv of the hypochlorite converted forations 13 and 12, andout through the valve 15. 'lFhe pole changer 9 is then swung into the opposite position, whereby 11 becomes .the anode and 10f-the cathode. rst portions of the liquid thus dowing in the opposite direction will carry substanrte" tially the entire amount of accumulated precipitated matter, leaving the electrodes clean. y

During the operation, practically none ot the chlorin liberated will. rise to the surtace of the liquor in the cell, the Vchlorin in absorbed quantitatively and Substau iet ' locating tially instantaneously by the ,caustic soda solution. The hydrogen liberated atthe cathode never comes'into contact with the hypochlorite solution, and will accordingly uicklyv rise to the surface and w1ll be drawn'oif through vthe pipe 7.

The inlets and outlets for the liquor are preferably placed, as illustrated, at or near the bottom of the cell, whereby the cell can easily be cleaned. Another advantage 1n the inlets and outlets at near the bottom of the cell is that the liquor in the vicinity of the anode is maintained at a low temperature, this being conducive `to high eiiiclencyv of production and also this reduces the tendency to the formation of chlorate.

On account of the fact that the hyurogen is evolved entirely out of contact with the hypochlorite solution, there is substantially no reduction of hypochlorite by the nascent hydrogen produced, hence the liquid is not heatedA up and the production of chlorate from hypochlorite is reduced to a minimum. In some -instances it might beadvisable to omit the cover 16 of the cell and to allow the hydrogen gas to pass to waste. Ordinarily, however, itis advisable to provide a cover andto draw ofi' this hydrogen through pipe 7 for use for any desired purposes. f

he cell is .particularly useful in connection with the production of hypochlorite from common salt which material frequently contains small quantities of magnesium salts, calcium salts, etc., which metals are liable to be deposited as hydroxids on the cathode. By reversal of the direction of'the current and by reversal of the direction of the solution, Ain a short time the precipitated hydroxids` will either be converted into soluble compounds or will be readily loosened from the tsurface of the electrode and will flow out with the! solution within a very short time after reversal of the ow.

A modified form of execution of the process within the scope of the present invention maly:` be carried on with an apparatus shown in igs. 4 and 5, Fig. 4 being a central' vertical section (partly in elevation) and Fig. 5 being a top plan view', of such modified form of apparatus.

In the apparatus shown in `Figs. 4 and 5, 20 is a cylindrical receptacle which may be open at the top and which contains centrallyy located therein a vertical tubular perforated anode 21. The cell is provided with suitable cathodes for example a' lining 22 of graphite or in some instances, metal. Also if desired,

(l suitable metallic vertical cathodes could be trolling the iiow of the brine.

employed. The brine is fed in through a. pipe 23, at the top of the cell, a suitable valve being provided in this piple for cone pipe 21 which is perforated with numerous sm holes 24 at various points in itspheight is continued downwardly through the bottom 25, which may be conveniently madeof an insulating-material, suitable plates 26 and graphite instead of merely having a lining 22 of graphite. In this case a convenient mode of attaching the cathode t'o the current supply 'would' be a strap or belt of metal surrounding the cell, either at its top or bottom or some intermediate point.

, The anode 21 may likewise consist of graphite, and may be connected to the source of electricity by a metallic ring 30 surrounding the Ianode 21, for example at its top. If desired, the .electrical connection could also be made to the pipe 28.

I claim:

1. A' process of making hypochlorite solu.- tion, which comprises passing a solution consisting essentially of an alkali metal chlorid through an electrolytic cell, and causing the liquor to flow from the cathode toward `and into contact with the anode.

and through perforations therein, whereby chlorin given off at the anode is set free in the presence of free caustic soda and then passing the solution out of theV cell, immediately after passing through the perforations in the anode, whereby contamination of the solution is minimized.

3.. A process of continuously producing hypochlorite solution which comprises passing a solution consisting essentially of water and an alkalimetal chlorid, and-containing some impurities, through an electrolytic cell, by. introducing the-said solution in the vicinity of the cathode, and allowing the same to flow in contact with such cathode, then toward and into contact lwith the anode and then out of the cell, and when insoluble impurities have been deposited upon one of said electrodes, reversing both the polarity of the electrodes and the direction of low of the liquor through the cell.

4. The process of producing hypochlorite solution yby passing a solutlon consisting largely of alkali metal chlorid through an electrolytic cell, first in contact with the cathode and thereafter .in contact with the anode, whereby any precipitation of impurities inthe alkali metal chlorid solution is produced largelgein the vicinity of the cath ode, the liquor ing introduced at near the all bottom of the celland also being withdrawn at near the bottom of the cell.

meme@ i 5. An electrolytic cell comprising a conintroducing liquor to be treated in proximity tainer, an anode' and a cathode therein, a to said cathode and means for withdrawing l0 liquor inlet to each end of said cell, a liquor liquor from said cell, in the Vicinity of said outlet from each end of the said cell, and a anode, whereby liquor is caused to flow to- 5 pole-changer in the delectrical connections ward said anode and away from said cathode. leading to said electrodes. In testimony whereof I aix my signature.

6. An electrolytic cell comprising a con- A tainer, a cathode and an anode, means for HENRY B. SLATER. 

